This invention relates to a dynamometer torque arm capable of measuring torque supplied by a dynamometer without recalibration with changes in the distance between center of rotation of the dynamometer and the reaction support of the torque and to a dynamometer assembly including a torque arm for measuring torque, horse power and/or rpm of engines particularly, although not exclusively, to engines without removal from an associated vehicle such as snowmobiles, motorcycles, chain saws, and lawn mowers. More particularly the invention provides an easily portable form of such a dynamometer assembly.
Dynamometers typically utilize a water brake to measure the torque of a rotary power source such as an internal combustion engine, with the torque being calculated from the reaction force necessary to hold a torque arm stationary at a fixed predetermined distance from the center of rotation of the water brake with the torque arm itself being affixed to the housing of the water brake. Such an arrangement is quite satisfactory in permanent installations but does not lend itself to universal portable dynamometers in which the dynamometer will be used in a number of different applications, perhaps with an internal combustion engine remaining installed in a vehicle while being tested by the dynamometer in which the distance from the center of rotation of the water brake to the reaction support point will be determined by the structural layout of the vehicle and the engine concerned and will in all probability vary from application to application with the consequent need or desire to recalibrate the dynamometer with each change in that distance if accurate readings are to be achieved.
It is an object of the present invention to provide a torque arm for a dynamometer capable of providing an accurate reading of torque without recalibration over a significant range of distances between torque center and reaction support for the torque arm.
It is a further object of the present invention to provide a dynamometer assembly including a torque arm according to the invention which is readily transportable and suitable for use to ascertain the torque and the horse power of an engine or motor mounted in the equipment in which its operation is associated.